1. Field of the Invention
This invention relates generally to conferencing and more particularly to systems and methods of audio teleconferencing using a conferencing bridge. Even more particularly, embodiments according to the present invention relate to the conferencing of high-fidelity and conventional callers, over traditional and network-based (e.g., Internet) connections.
2. Background
Generally, forms of conference calling have been offered as a telecommunications service for some number of years and such service is relied upon by many businesses. As prices have dropped for conferencing equipment and conference hosting, conferencing has become increasingly popular and is now used by businesses and some consumers on a regular basis for local, national, and global virtual meetings. Participants typically dial into a conference “bridge”—a specialized system connected to the telephone network. The participants enter DTMF digits to identify the conference they wish to join. Once established, the system computes and sends to each participant the merged audio of the other participants. Specialized processing can eliminate echoes and noise and automatically equalize volume. The audio quality of the conference is limited to the capability of conventional telephone instruments and networks, which generally support about 300 to about 3500 Hertz frequency response using coder/decoder (codec) technology standardized by the ITU as G.711. This quality level, generally referred to as “narrowband,” is generally adequate for conversational speech, but it can make it harder to recognize voices, discern certain phonetic sounds, separate speech from background noise, distinguish multiple simultaneous speakers, and hear soft or whispered speech.
In some instances, participants in a telephone conference can be physically co-located in a conference room. Telephone instruments called speakerphones or conference phones allow these participants to speak and listen normally without having to hold a handset. These conference phones can be used in a point-to-point configuration, where a group in one conference room calls to a conference phone in another, remote conference room, and the two groups can interact via a telephone connection. Alternatively, the conference phone can be used to dial into a conference bridge, described above. Thus, in some instances the participants on the bridge may include groups using conference phones as well as individuals with handsets.
Manufacturers of conference phones have introduced enhanced endpoint devices having encoding technology configured to capture sound at higher fidelity, offering a frequency response from about 80 to about 7000 Hertz (generally referred to as “wideband”), and producing a noticeably better audio experience. This allows participants to more readily recognize voices and to better understand what is said by a remote speaker. Typically, this enhanced audio capability is only operational when the endpoint device is operating in the point-to-point mode connected to another like device. In these instances, the endpoint device avoids limitations imposed by the telephone network (PSTN) by establishing a digital connection between two enhanced endpoint devices using modem technology, and then digitally sampling, encoding, and compressing the high-fidelity audio signal and exchanging it via the digital connection. If an enhanced endpoint device attempts to connect to a conventional conference bridge (i.e., a narrowband bridge), the narrow-band bridge is incapable of establishing the digital connection and the enhanced endpoint device is forced to revert to lower-fidelity, analog audio. One example of a manufacturer of enhanced endpoint devices is Polycom (Polycom, Inc., Pleasanton, Calif.), providers of a system designated VTX-1000™, which uses special encoding technology to capture sound at higher fidelity.
In addition to connections over the conventional telephone network, an increasing number of “telephone calls” are made over the Internet utilizing technology commonly referred to as Voice-over-Internet-Protocol, or VoIP. These calls are made with special Internet telephones, with adapters that interface traditional phones to the Internet, or with Internet-connected personal computers augmented with headsets and special software. Most commonly, Internet calls mimic the audio quality of traditional telephony, and in many cases can communicate with conventional bridges or with bridges specially interfaced to the Internet. Some Internet telephone systems have technology for higher-fidelity audio; this capability generally applies only in point-to-point communications with like (or compatible) devices. For a variety of technical reasons, it is easier and cheaper to implement wideband audio in the Internet domain, so this option is becoming increasingly common as Internet telephony grows in popularity. Skype™ (Skype™ is an eBay, Inc. company, San Jose, Calif.) and GoogleTalk™ (Google Inc., Mountain View, Calif.) are examples of commercially-available high-fidelity VoIP-based networks.
Because current conferencing technology sets the frequency response to the lowest common denominator of the endpoint devices accessing a bridge, in many instances enhanced or wideband endpoint devices are not able to utilize their greater fidelity when participating in conferences that also include narrow-band endpoint devices. Embodiments according to this invention provide a way to overcome these challenges, some of which are described above.